-- 099: Government-fee child orders for at-cost compliance services.
--
-- At-cost services (IRP, IFTA, intrastate authority, etc.) collect only our
-- SERVICE fee at checkout; the actual government/state fee is variable and
-- "billed at cost" afterward. To collect it we create a CHILD compliance_orders
-- row (service_fee_cents = 0, gov_fee_cents = the quoted state fee) that flows
-- through the EXISTING checkout/payment-picker/webhook machinery unchanged, and
-- email the customer a payment link with every payment method + correct
-- surcharges. parent_order_number links that child back to the original order so
-- the worker can resume filing once the fee is paid.
--
-- Idempotent.

ALTER TABLE compliance_orders
  ADD COLUMN IF NOT EXISTS parent_order_number text;

-- Look up a parent's gov-fee children quickly (and vice-versa).
CREATE INDEX IF NOT EXISTS idx_compliance_orders_parent
  ON compliance_orders (parent_order_number)
  WHERE parent_order_number IS NOT NULL;